[Air-L] About estimation of quantity of Tweets per keyword

Hello everyone, I know that this question might not have an answer given the changes Twitter has gone through in the last year, but I thought it was worth a shot. Is there any online tool that could estimate the quantity of Tweets containing a keyword within a specific time frame?  Regards, Xanat V. Meza Ph.D. Kansei, Behavioral and Brain SciencesUniversity of Tsukuba M.A. Media and Communication Yeungnam University B.D. Graphic Communication Design Universidad Autonoma Metropolitana